There’s always a sense of immense relief when a movie isn’t as bad as you think it’s going to be.

“Teenage Mutant Ninja Turtles,” the Michael Bay-produced incarnation of the four green superheroes many of us know either through our kids or our own childhood, manages to do a surprisingly decent job of bringing the titular turtles to life. The rest of the movie isn’t that great, but if you’ve missed hanging out with the shellheads (or their sensei/father figure, Splinter) it’s not a bad way to spend a few hours.

The story elaborates on the ninja turtles’ origin, turning the green ooze into a mutagenic serum that is inevitably part of a nefarious plan to harm the city of New York. Several fights, a lot of crashes and a few dramatic villain speeches follow, all completely generic and seemingly duct-taped together to make a movie length script. The dozens of plot holes – how exactly did the turtles afford the supplies to make their high-tech security system, for example – are completely ignored.

Intrepid reporter April O’Neal is also given more to do, becoming the turtles’ savior after a mysterious lab fire when she was a child. Sadly, this is the least interesting or pro-active April I’ve ever seen in any version of TMNT, mostly there to either scream or look confused at key moments.

Surprisingly, it seemed to be more the script’s fault than it is Megan Fox’s, constantly hampering her with lines and situations that make her seem both incredibly naïve and occasionally flat-out stupid. A better actress might have saved some of the more ridiculous scenes, but Fox was clearly trying her hardest.

The turtles, thankfully, come off much better. Their personalities are similar to that found in the cartoons – Leonardo is the responsible one, Michelangelo is almost a goofball, Donatello invents stuff – though here Raphael tends to be more angry than sarcastic. Their mix of affection and argument was nicely brotherly, with some of the best dialogue going to the easy banter between them.

This is also the first TMNT interpretation to remind me that “teenager” is a part of the title, which I considered a pleasant surprise. For all their muscularity, the turtles come off as very young, that shifting mixture of boldness, burgeoning responsibility and recklessness characteristic to teenage boys of any species. The fact that they managed to do this and not be annoying is a credit to all four voice actors. Splinter, voiced by Tony Shaloub, was very sweet (and put up quite a CGI-assisted fight).

The other unexpected treat was Vernon Fenwick, a character who was probably supposed to be completely ignored until Will Arnett got a hold of him. A cameraman who works with April, Arnett turns Vernon’s handful of lines into a surprisingly dry delight that made me happy every time he came onscreen. In fact, I wouldn’t have minded shuffling April offstage to give him even more screen time.

After all, even a mediocre movie isn’t so bad when you have good characters to keep you company.